High pressure ball valve

ABSTRACT

A ball valve designed for high pressure shut-off at fluid pressures approaching the ultimate compressive stress of plastic annular seat rings which are employed. The ball member is trunnion mounted in order to carry the total force of the shut-off pressure and the seat rings are disposed in seat ring carriers. Each seat ring includes a spherical ball engaging surface having a radius slightly smaller than the radius of the ball. Each carrier is continuously urged toward the ball by a plurality of disc springs in order that the seat ring engaging surfaces will be in continuous sealing engagement with the ball surface. The seat ring engaging surfaces are configured so that at least the areas thereof located adjacent the outer diameters will be first to sealingly engage the ball. The valve components are configured and dimensioned to limit the effective area on which fluid pressure may act in urging the seat rings into ball contact for thus controlling compressive stresses which may be exerted on the plastic seat ring material. Also, fluid pressure urges the seat rings toward the ball to enhance sealing engagement with the ball regardless of the position of each seat ring upstream or downstream of the ball from the source of fluid pressure and also with the valve in the open position. The inventive concept involved may advantageously be employed in a variety of valve bodies to accommodate a plurality of fluid shut-off applications.

BACKGROUND OF THE INVENTION

This invention relates to the valve art and more particularly to ballvalves.

The invention is particularly applicable to a new high pressure ballvalve and will be described with particular reference thereto. However,it will become readily apparent to those skilled in the art that theinvention is capable of broader applications and could be adapted to usein other types and styles of valves.

Typically, ball valve constructions in commercial use employ annularseats or seat rings formed of a plastic material. For large ball valvesor for ball valves specifically designed for high pressure use (aboveapproximately 2500 psi), the ball member is usually trunnion supportedwith these valve seats or seat rings having the capability of floatingand being pressure activated to seal against the ball. However, in suchlarge size and high pressure ball valves, some steps must be taken tolimit the amount of fluid pressure which will act on the seats toprevent the imposition of destructively high compressive stressesthereagainst.

Therefore, and in order to eliminate compressive stresses of a magnitudewhich may severely damage or destroy the seats or seat rings, it hasbecome necessary to employ pressure controlled seats in conjunction witha bearing or trunnion supported ball. While some valve constructions ofthis type are known in the art, the specific constructions andoperational details thereof have not satisfactorily met the needs ofindustry. In particular, some prior designs have involved verysophisticated and/or cumbersome structures which cause productiondifficulties and add to the valve costs. Other prior designs of thistype are for special or limited applications and are not adapted togeneral high pressure shut-off applications. Still other prior highpressure valves have involved constructions which, after relativelyshort periods of use, would not properly function and alloweddestructive forces to be imparted to the valve seats.

It has, therefore, been desired to develop a high pressure ball valvewhich would overcome the foregoing problems. Such a design woulddesirably utilize a trunnion mounted ball with plastic seats, beadaptable to use in a wide range of applications or environments and beeffective for a large number of valve cycles. The present inventioncontemplates a new and improved high pressure ball valve constructionwhich is deemed to meet all of the foregoing needs and others.

BRIEF DESCRIPTION OF THE INVENTION

The present invention is directed to a high pressure ball valve whichemploys a trunnion mounted ball member to carry the total force of thesystem shut-off pressure. Plastic seat rings carried by seat ringcarriers are continuously urged by spring biasing means into sealingengagement with the ball member. The valve components and relationshipstherebetween are specifically designed to limit the effective area onwhich fluid pressure may act in order to control compressive stressesexerted on the plastic seat rings.

More particularly in accordance with the invention, the valve includes abody having a cylindrical first flow passageway extending therethroughand a cylindrical central passageway communicating with the firstpassageway in a direction generally normal thereto. A valve closuremember is positioned in the central passageway and mounted for selectiverotation about the central passageway axis. This closure member has aspherical or ball portion disposed in the first passageway and a pair ofcylindrical portions or trunnions disposed on opposite sides of the ballportion. The ball portion includes a fluid passage therethrough and oneof the trunnions includes means for connecting the valve closure memberto external control means. A pair of radially inward extending annularshoulders are located in the first passageway on generally oppositesides of the ball portion and spaced at generally equal distancestherefrom, each shoulder being circumferentially continuous and facingthe ball portion. A pair of seat ring carriers are disposed in the firstpassageway with each carrier including an axial fluid flow openingtherethrough and a radially outward extending surface facing anassociated one of the shoulders. The carriers each further include anannular seat ring receiving groove facing the closure member ballportion and a cylindrical tail portion extending axially of the firstpassageway away from the closure member in radially spaced relation to acylindrical seal chamber. A plurality of partially stressed disc springsare interposed between each shoulder and the radial surface of theassociated carrier for urging the carriers axially of the firstpassageway toward the ball portion. A deformable annular seat ring isclosely received in the seat ring receiving groove of each carrier witheach seat ring including a continuous ball portion engaging surface. Inits unstressed condition, this engaging surface has a sphericalconformation of a radius smaller than the radius of the ball portion.The seat ring engaging surfaces are urged into sealing contact with theball portion under the influence of the disc springs with such sealingcontact occurring at least at a diameter across the engaging surfaceswhich is smaller than the diameter across the associated seal chamber.Seal means is interposed between each carrier tail portion and theassociated seal chamber with this seal means including at least oneannular seal ring adapted for axial shifting between defined limits inresponse to fluid pressure exerted thereagainst. Finally, a controlmeans is disposed in operative communication with the valve closuremember connecting means to accommodate selective rotation of the closuremember for moving the ball portion fluid passage between valve openedand closed conditions. The valve construction limits an annular area onwhich fluid pressure may at any time act for urging the seat ringstoward the ball portion in either the valve opened or closed conditionto a maximum which is related to the area of sealing contact between theseat ring engaging surfaces and the ball portion.

In accordance with another aspect of the invention, each seat ringengaging surface contacts said ball portion by an annular engaging band.This band has an outer diameter greater than the outside diameter of theassociated carrier tail portion and an inside diameter which is lessthan the diameter of the associated seal chamber. The preciserelationship between the annular fluid pressure area and the annularengaging band is determined by the maximum fluid shut off pressure andthe desired maximum compressive stress to be placed on the seat ringmaterial. The lesser the radial thickness of the annular fluid pressurearea, the lesser the compressive stress exerted on the seat ringmaterial.

According to a further aspect of the invention, the valve closure memberis located and retained in the valve body central passageway by the seatrings. In addition, the closure member is pressure balanced in thecentral passageway so that it will not be urged outwardly therefrom byfluid forces.

In accordance with another aspect of the invention, the shoulders in thefirst passageway and the seal chambers are defined by removable endfittings received in the first passageway.

According to another aspect of the invention, the control meanscomprises an operating stem rotatably received in the central passagewayand having an outer end disposed outwardly of the valve body. The stemincludes a radially outward extending circumferential flange adjacentthe stem inner end cooperable with a radially inward extending flange inthe central passageway to prevent stem withdrawal in the direction ofthe stem outer end. In the preferred arrangement, a stem bearing isadvantageously interposed between the stem and central passagewayshoulders and a control handle is secured to the stem outer end toaccommodate valve closure member shifting between valve open and closedconditions. The valve body includes a handle stop for engagement by stopsurfaces on the handle when the valve is disposed in one of the open andclosed conditions.

Preferably according to the invention, one of the stem inner end and thevalve closure member trunnion includes an axial tang and the other ofthe stem inner end and the one trunnion includes a tang receiving slot.The tang is received in the slot for interconnecting these twocomponents and comprises the only contact between the stem and valveclosure member. Such relationship advantageously prevents anydisturbance in the axial located position of the valve closure memberwithin the body central passageway in the event there is slight axialshifting of the operating stem during valve use or operation.

In accordance with one structural embodiment which incorporates theinvention, the closure member trunnions include seal means which sealagainst the side wall of the central passageway. Also, the stem includesa vent opening to vent any fluid bypassing the seal means of the onetrunnion in order to maintain the closure member in a pressure balancedcondition.

According to still another aspect of the invention, the valve closuremember fluid passage includes a portion extending therethrough betweenthe closure member trunnions. In addition, that portion of the centralpassageway which receives the other trunnion includes means adapted forconnecting a fluid line thereto for allowing the valve to accommodatefluid flow between at least three fluid lines.

The principal object of the invention is the provision of a new highpressure ball valve which utilizes a trunnion mounted ball member andplastic seat rings.

Another object of the invention resides in a new high pressure ballvalve which minimizes the effective amount of fluid pressure which mayact to urge the seat rings into engagement with the ball.

Another object of the invention is the provision of such a ball valvehaving a fairly simple design which is extremely effective for a highnumber of shut-off cycles.

Still a further object of the present invention is the provision of anew ball valve which is readily adapted to use in a wide variety ofapplications and/or environments.

Still other objects and advantages of the invention will become apparentto those skilled in the art upon a reading and understanding of thefollowing specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may take physical form in certain parts and arrangementsof parts, preferred and alternative embodiments of which will bedescribed in detail in this specification and illustrated in theaccompanying drawings which form a part hereof and wherein:

FIG. 1 is a side elevational view of the subject new high pressure ballvalve;

FIG. 2 is a cross-sectional view of the valve body;

FIG. 3 is a partial cross-sectional view of the valve closure member;

FIG. 4 is an exploded cross-sectional view of one end fitting, a seatring carrier and the associated components utilized in the new valve;

FIG. 5 is a cross-sectional view of the valve shown in FIG. 1;

FIG. 6 is an enlarged view of a portion of the valve shown in FIG. 5 forbetter illustrating the cooperative relationships between the seatrings, seat ring carriers, seal means, disc springs and end fittings;

FIG. 7 is a cross-sectional view similar to FIG. 5 showing analternative valve construction which incorporates the concepts of thesubject invention; and,

FIG. 8 is an enlarged cross-sectional view of a portion of the valvewith the seat ring carrier shown in a slightly retracted position fromthe ball portion for showing the relationship between the radii of theball portion and the seat ring engaging surface in accordance with theinvention.

DETAILED DESCRIPTION OF THE PREFERRED AND ALTERNATIVE EMBODIMENTS

Referring now to the drawings wherein the showings are for purposes ofillustrating preferred and alternative embodiments of the invention onlyand not for purposes of limiting same, FIGS. 1, 3, 4 and 5 show the newhigh pressure ball valve as generally being comprised of a valve body A,a closure member B, a pair of seat ring carriers C, a pair of endfittings D, an operating stem E and a handle F.

More particularly, and with primary reference to FIG. 2, valve body A isfor a two-way valve and includes a first fluid passageway 10 extendingtherethrough between branches 12,14. Each branch is internally threadedas at 16 for receiving end fittings D as will become apparent. Inaddition, each branch includes an outwardly facing radial shoulder 18spaced axially along first passageway 10 from the outer ends thereof.

A cylindrical second or central passageway 20 extends through body Abetween an externally threaded bonnet 22 and a lower end 24. Thiscentral passageway is disposed generally normal to first passageway 10and communicates therewith as is shown to define a valve chamber.Central passageway 20 includes a smaller diameter portion 26 adjacentthe upper end of bonnet 22 which acts to define a downwardly facingradial shoulder 28. An opening 30 in the upper face of bonnet 22receives a pin-like handle stop as will become apparent. Also, a panelnut 32 is received on the external bonnet threads to accommodate valvemounting as is known.

FIG. 3 shows closure member B as including a spherical or ball portion40 and a pair of cylindrical portions or trunnions 42,44 on oppositesides thereof. The ball portion and trunnions are interconnected atsmaller diameter neck areas 46. A fluid passage 48 extends through ballportion 40 transversely of trunnions 42,44 to permit selective controlof fluid flow through the valve between branches 12,14 as isconventional.

A centrally located tang 52 protrudes axially outward of closure memberB from the end of trunnion 42 for reasons and purposes which will bedescribed. Each of the trunnions includes a circumferential groove 50having an O-ring 54 and a backup ring 56 received therein. Trunnions42,44 are dimensioned to facilitate close fitting receipt of closuremember B in body central passageway 20 so that the closure member may beselectively rotated in the central passageway to effect valve openingand closing as will be described. When installed, one trunnion of theclosure member is disposed on each side of body first passageway 10 withball portion 40 disposed in the first passageway (FIG. 5). The maximumcross-sectional dimension of the ball portion is less than the diameterof central passageway 20 with O-rings 54 and backup rings 56 acting toprevent fluid leakage between closure member B and body A.

FIG. 4 shows an exploded cross-section of one seat ring carrier C andone end fitting D with associated components. It should be appreciatedthat one of the structures shown in FIG. 4 is associated with each ofvalve body branches 12,14 and that both structures are identical unlessotherwise specifically noted. More particularly, carrier C includes acylindrical forward portion or head 60 and a cylindrical tail portion 62extending coaxially from the head. A fluid flow opening 64 extendsthrough portions 60,62 and an annular shoulder or surface 66 is definedat the interface therebetween. The forward end face of head 60 isbevelled as at 68 and includes an annular seat ring receiving groove 70.The outside diameter of head 60 is slightly smaller than the diameter ofbody first passageway 10 axially inward of shoulders 18 (FIG. 2).

End fitting D includes a body 80 externally threaded as at 82 forthreaded cooperation with threads 16 of branches 12,14 (FIG. 2) as willbecome apparent. A fluid flow opening extends axially through the bodyand is comprised of a forward portion 86, a smaller diameter centralportion 88 and an enlarged rear portion 90. Rear portion 90 is threadedas at 92 for purposes of receiving a conventional fluid fitting when thevalve is installed in a fluid system. A circumferential groove 94 isdisposed at the forwardmost end of body 80 and receives a seal 96 toeffect fluid sealing between end fitting D and valve body A in theassembled valve. As shown, seal 96 comprises an annular ring machinedfrom a polymeric material. However, the seal may also be comprised of anO-ring, a soft metal or any other suitable seal material.

The diameters of fluid flow opening central portion 88 and carrier tailportion 62 are such that there will be a close guiding relationshiptherebetween at valve assembly. Flow opening forward portion 86 has alarger diameter than the carrier tail portion and acts to define acylindrical seal chamber. At valve assembly, tail portion 62 is radiallyspaced from the side wall of forward portion 86 with appropriate sealmeans being interposed in the annular area defined therebetween. Anannular section of end fitting body forward end face 98 is adapted toengage body first passageway shoulder 18 at valve assembly. Thisprovides a positive forward stop for end fitting D in its mountedrelationship with valve body A. The remaining annular section of forwardend face 98 defines a shoulder which faces radial surface 66 of seatring carrier C. There is significant cooperative interplay between thesetwo surfaces as will become apparent hereinafter.

Also included in the carrier C and end fitting D arrangement of FIG. 4is a seal means for end fitting seal chamber 86. In the preferredarrangement shown, this seal means is comprised of an O-ring seal 100and a pair of backup rings 102,104 on opposite sides of the O-ring.These elements are dimensioned for receipt in the annular area definedbetween seal chamber 86 and carrier tail portion 62. In the preferredconstruction, O-ring 100 and backup rings 102,104 are constructed frompolymeric materials. An annular gland 106 is dimensioned for receipt inchamber 86 over carrier tail portion 62. This gland acts to provide apositive stop for back-up ring 104 in the assembled valve and isdimensioned to prevent extrusion of ring 104 therepassed under fluidpressure conditions. At the same time, gland 106 accommodates slightlateral movement of carrier C for reasons to be described.

A plurality of disc springs 110,112,114 are advantageously provided forcontinuously urging seat rings associated with carriers C into sealingengagement with the surface of spherical or ball portion 40 (FIG. 3) ina manner to be described. Although three such disc springs are shown, itshould be appreciated that a greater or lesser number of them may beemployed to better accommodate various valve construction details and/oroperating parameters. In their unstressed condition as shown in FIG. 4,disc springs 110,112 and 114 have a generally frusto-conicalconformation and include a central opening dimensioned to accommodatedisc spring receipt over carrier tail portion 62. The outside diameterof the disc springs is slightly less than the diameter of valve bodyfirst passageway 10 at the area thereof disposed axially inward ofshoulders 18. At assembly, the disc springs are partially stressedtoward a flattened condition between the opposed shoulders defined bycarrier radial surface 66 and fitting body forward end face 98. As willalso be noted, the disc spring which will engage surface 98, viz., discspring 110 has its smaller diameter end facing toward carrier head 60.This assures that the spring will react against rigid surface 98 and notwith gland 106 as would be the case if the smaller diameter end of thedisc spring faced away from carrier head 60. The other of the discsprings, viz., springs 112,114, are disposed in alternating positions asshown. Such an alternating relationship is also employed in cases wherea greater or lesser number of disc springs is employed. Use of aplurality of disc springs is considered desirable and advantageous forpurposes of acting as a tolerance take-up device while stillaccommodating a carrier biasing function in a manner to be described.

Finally with regard to FIG. 4, an annular seat ring 120 is provided andis dimensioned to be closely positioned in carrier seat ring receivinggroove 70. This seat ring may be constructed from any plastic materialhaving those physical characteristics desired for a particular valveapplication. The seat ring includes a spherical ball portion engagingsurface 122 and a narrow annular zone 124 communicates between the seatring outer periphery and engaging surface 122 to provide additional seatring strength or support at that area.

In practicing the concepts of the subject invention, it is particularlydesirable to have full surface contact between seat ring engagingsurface 122, i.e., between engaging surface inner and outer diameters126,128 and ball portion 40 of closure member B. In this desirable mode,the seat ring engaging surface thus contacts the ball portion by anannular contact or engaging band defined between inner and outerdiameters 126,128. Outer diameter 128 is greater than the outsidediameter of the associated carrier tail portion 62. With thisrelationship, and when seat ring 120 is positioned downstream from ballportion 40, fluid pressure will urge carrier C toward the ball portionso that the seat ring, in turn, will be further urged against the ballportion to thereby enhance its sealing function. Inner diameter 126 isless than the diameter across the associated seal chamber 86. As aresult, when seat ring 120 is positioned upstream from the ball portion,fluid pressure will again urge carrier C toward the ball portion toenhance the seat ring sealing function. Therefore, regardless of theposition of the seat ring with respect to fluid flow, and independent ofthe other seat ring in the overall valve assembly, fluid pressure willact in conjunction with the disc springs to urge the carrier toward theball portion for enhancing the seat ring sealing function.

In actual practice, however, because of component tolerances, it isdifficult to precisely match spherical seat ring engaging surface 122and ball portion 40 for obtaining full surface contact therebetween, atleast at the initial valve assembly. Upon such assembly, the seat ringengaging surface and the ball portion will typically form a line contactcircumscribing ball portion fluid passage 48 (FIG. 3) at a diameterbetween inner and outer diameters 126,128. In order to insure that theseat rings properly seal in any case or situation of seat to ballcontact, it is necessary to set the dimensions of both components sothat as the seat ring engaging surface is brought into contact with theball portion by assembly of the components, engaging surface 122 firstcontacts the ball portion with a line contact at or adjacent to engagingsurface outer diameter 128. Since this outer diameter is set smallerthan the diameter across the associated seal chamber 86, the carrier isstill urged by fluid pressure toward the ball portion when upstreamtherefrom. Conversely, if the dimensions of both the seat ring engagingsurface and ball portion were set such that the seat engaging surfacefirst contacts the ball portion with a line contact at or adjacent toengaging surface inner diameter 126 at initial assembly of thecomponents, fluid pressure may actually urge carrier C away from theball when it is in the downstream position. This unacceptable result mayoccur since the engaging surface inner diameter may not be greater thanthe outside diameter of the associated carrier tail portion 62.

Accordingly, and to insure that engaging surface 122 will always firstcontact ball portion 40 with a line contact at or adjacent engagingsurface outer diameter 128, the spherical shape of the engaging surfacehas a radius smaller than the radius of the ball portion (FIG. 8). Thedifference between the radii of seat ring engaging surface 122 and ballportion 40 must be small enough such that an appreciable contact orengaging band width, e.g., approaching the desirable full annular bandbetween seat ring inner and outer diameters 126,128, is generated withthe application of low fluid pressures or by the force provided by discsprings 110,112 and 114. The difference in radii may also vary somewhatas a function of the particular seat ring material employed and/or otheroperating parameters.

Thus, once valve assembly is completed, the initial line contact betweenengaging surface 122 and ball portion 40 is automatically widenedapproaching the desirable full annular contact band from outer diameter128 toward inner diameter 126 by ensueing spring and fluid pressureloads. Such loads cause the plastic seat material to deform against theball. The engaging relationship between the seat ring engaging surfaceand ball portion is further enhanced by wear of the plastic seat ringmaterial caused by cycling the valve assembly.

Moreover, in the desirable mode of full surface contact between seatring engaging surface 122 and ball portion 40, the subject inventionlimits the compressive force which could otherwise destructively crushthe seat material. When the seat ring is located in an upstreamposition, compressive force is caused by the action of fluid pressure inthe annular area defined between the diameter across the associated sealchamber 86 and inside diameter 126 of the seat ring engaging surface.When the seat ring is located in a downstream position, this compressiveforce is caused by the action of fluid pressure in the annular areadefined between outside diameter 128 of the seat ring engaging surfaceand the outside diameter of the associated carrier tail portion 62.Specifically, the ratio of this annular area to the projected annulararea of seat ring engaging surface 122 between diameters 126,128 isequal to the ratio of the fluid pressure to the compressive stress onthe seat. Thus, in practicing the concepts of the subject invention,these annular areas are adjusted such that common plastics may be safelyused as seat materials and effectively seal against high fluidpressures.

FIG. 5 best shows the structural arrangements for stem E and handle F.More particularly, the stem includes a cylindrical body portion 130closely rotatably received in smaller diameter portion 26 of bodycentral passage 20. This body portion has a circumferential groove 132which includes a polymeric or elastomeric journal bearing 134. Thisbearing inhibits metal to metal sliding contact between the stem andvalve body as the stem is rotated. This then reduces operating torqueand provides the valve with a smooth-to-the-touch feel upon operation.The bearing also fills the gap between the stem and central passageway20 to eliminate any looseness at the handle. A radially outwardextending flange 136 having a circular cross-section of a diameterslightly less than the diameter of body central passageway 20 isprovided at the stem inner end. A lateral groove 138 is included in theend face of flange 136 to receive tang 52 of valve closure member B andthus place the stem and closure member in cooperative engagement witheach other. Stem E further includes an outer or handle receiving end 140disposed outwardly of the valve body adapted to receive handle F. A leakport 142 extends axially of the stem from the end face of flange 136toward stem outer end 140. Radial cross branches 144 communicate withport 142 at a location disposed externally of the valve body. The leakport insures expeditious venting to atmosphere of any leakage of fluidpressure that might pass O-ring seal 54 on trunnion 42. Without thisvent, such leakage could build up pressure between stem E and closuremember B and thus urge the closure member outwardly of centralpassageway 20 at body end 24.

An annular stem bearing 146 is advantageously interposed between endflange 136 and central passageway shoulder 28 to better facilitate easeof stem rotation. The metal-to-metal contact which would otherwise bepresent would render valve opening and closing more difficult andrequire more torque. In the preferred arrangement shown, this bearingmerely comprises an annular ring constructed from, for example,polytetrafluoroethylene.

Handle F includes a handle body 150 which, in the preferredconstruction, is molded from phenolic plastic. The handle body may takeany number of different or detailed configurations and includes anopening in the underside thereof for accommodating installation ontohandle receiving end 140 of the stem. This opening includes acylindrical metallic insert constructed from brass or the like whichclosely embraces handle receiving end 140. A dog point set screw 154extends through the handle body, insert and stem receiving end 140 formaintaining a fixed association between handle F and stem E.

A stop 158 which takes the form of a pin or the like is received in bodyopening 30 and is dimensioned to extend a short distance upwardly fromthe outer face of valve body bonnet 22. Handle body 150, in turn,advantageously includes a pair of arcuately spaced apart handle stops inan enlarged area of the handle opening. One such stop is designated bynumeral 156 in FIG. 5 and the pair of stop surfaces in combination withstop 158 limit handle rotation to between a pair of predeterminedmaximum rotated positions. The mounting of the handle to the stem, thestem relationship to the ball closure member, the location of pin 158and the locations of the handle stop surfaces are coordinated so thatwhen one of the handle stops is in engagement with pin 158, the valvewill be disposed in the fully opened position as shown in FIG. 5. Whenthe handle is rotated so that the other stop surface engages pin 158,the ball closure member will be moved to a valve closed position whereinclosure member B is rotated approximately 90° relative to the fullyopened position shown.

FIGS. 5 and 6 provide the best reference for the following discussion onvalve assembly. In particular, stem E with stem bearing 146 is firstinserted into central passageway 20 of valve body A from lower end 24thereof. Bearing 134 advantageously functions between the stem and theside wall of the central passageway in the manner previously described.Handle F may then be installed if desired for retaining the stempositioned in the valve body. Valve closure member B is next insertedinto central passageway 20 in such a manner that tang 52 is received ingroove 138.

It should be noted that the end face of stem flange 136 does notdirectly engage the upper face of the valve closure member and that aconnected relationship between these two components is effected solelybetween tang and receiving groove. The foregoing relationship isprovided and maintained by dimensions held on the stem, the closuremember, the valve body and the handle. If direct engagement between thestem and closure member is not prevened except at the interconnectionbetween tang 52 and groove 138, the stem and handle could be pushed byhand into the valve and, upon flange 136 engaging the upper face of theclosure member, push ball portion 40 out of sealing contact with seatrings 120.

O-rings 54 and backup rings 56 carried by trunnions 42,44 act to preventfluid bypass between the walls of central passageway 20 and valveclosure member B when the valve is placed in a fluid system. Ballportion 40 has a smaller diameter than body central passageway 20 and isreceived in the valve chamber defined at the intersection of passageways10,20.

Carriers C and end fittings D shown in FIG. 4 may then be assembled andinstalled into valve body branches 12,14 as shown in FIG. 5 withexternal threads 82 of the end fittings engaging internal threads 16 ofthe valve body. When each end fitting is fully inserted into the body,forward end face 98 thereof will engage the associated one of valve bodyshoulders 18. Seals 96 will prevent fluid by-pass between the endfittings and valve body.

The components included in the carrier and end fitting subassemblies aredimensioned such that when the end fittings are fully inserted into thevalve body, disc springs 110,112 and 114 will be partially stressedtoward a flattened condition between shoulder faces 66,98. Suchstressing will, in turn, act to urge carriers C toward closure member Bwith the seat ring engaging surfaces 122 contacting ball portion 40.Neck areas 46 on each side of the spherical portion accommodate thisrelationship. As previously noted, the seat ring engaging surfaces eachhave a slightly smaller radius than the radius of the ball portion.Moreover, the dimensions of the engaging surfaces and closure member areset so that at assembly, engaging surfaces 122 first contact ballportion 40 with at least a line contact at or adjacent engaging surfaceouter diameter 128. The spring force of the disc springs acting oncarriers C causes seat ring deformation so that the area of engagementbetween engaging surfaces 122 and ball portion 40 is widened toward thedesired full annular engaging band from outer diameter 128 to innerdiameter 126.

The use of multiple disc springs for biasing each of carriers C is alsodesirable to accommodate minor tolerance variations which may be presentin the valve components. Dimensioning of the valve components is suchthat the springs are, at worst, fully stressed to a flattened condition,but never beyond, between shoulders 66,98. Preferably, the disc springsare only partially stressed and are never loose. While the valveconstruction shown employs three disc springs cooperating with eachcarrier C, it will be appreciated that use of a greater or lesser numberof such springs may be desired for different valve sizes and/or toaccommodate various operating parameters.

Valve closure member B is retained in valve body central passageway 20through engagement of the seat ring engaging surfaces with the ballportion. Because of the dimensional relationships between carriers C,end fittings D and the associated components, the carriers may shiftslightly relative to the end fittings so that seat rings 122 sealinglyengage ball portion 40 as described above with the center of ballportion 40 being located at the intersection of the longitudinal axes ofvalve body first and central passageways 10,20. This feature thusaccommodates slight tolerance variations which may be present in thecomponents. In addition, valve closure member B may float slightlywithin body central passageway 20 to facilitate proper seat ring-ballportion alignment and eliminate the potential for operationaldifficulties on account of manufacturing tolerances.

Backup ring 102 associated with each carrier-end fitting is rigidlysupported at the shoulder-like interface between end fitting flowopening portions 86,88 and backup ring 104 is similarly supported bygland 106. Backup rings 102,104 are axially spaced apart from each otherin seal chamber 86 by a distance greater than the transversecross-sectional dimension of O-ring 100 in order that the O-ring mayfloat as a function of the direction of fluid pressure actingthereagainst to prevent fluid by-pass between the carriers and theirassociated end fittings.

With the above described two-way valve connected with a fluid system atbranches 12,14 and with valve closure member B in a valve closedcondition, i.e., with the closure member rotated 90° from the views ofFIGS. 5 and 6, system fluid will pass through the interior of the inletor upstream branch end fitting and carrier to act against ball portion40. Because of the carrier configuration, fluid pressure will act on theball to the inside diameter of engaging surface contact with the ballportion. At the same time, fluid pressure will act on the outer end ofcarrier tail portion and will pass between the carrier tail portion andend fitting to act against upstream O-ring 100 to urge it forwardlyagainst backup ring 104. As a result of the foregoing conditions, thetotal area under pressure for producing the force on closure member Bwhich is carried entirely by trunnions 42,44 is defined by the totalarea across upstream seal chamber 86. This force is quite large and, ifnot carried by trunnions 42,44, would apply a destructive load on thedownstream seat ring. With the subject invention, however, closuremember B is supported by the trunnions so that it may not move axiallyof valve body first passageway 10.

In accordance with the subject invention, the conformation of carriers Cwith seat rings 120, seal chambers 86 and end fittings D are such thatthe upstream seat ring seals the valve in a valve closed condition. Inaddition to the cooperative relationship between the componentsthemselves, particularly the relationship between seat ring engagingsurface 122 and ball portion 40 and the action of disc springs 110,112and 114, some fluid pressure will act to exert a force for urging theupstream seat ring into sealing engagement with the closed ball portion.Such force will enhance or increase the amount of seat ring engagingsurface 122 contacting the ball portion, i.e., increase the width of theengaging band from seat ring outer diameter 128 toward inner diameter126. In the preferred sealing mode, full surface contact between thesetwo diameters is desired in a manner previously described.

The area which provides the net force of fluid pressure acting onupstream seat ring 120 is limited to the annular area defined by theouter diameter of upstream seal chamber 86 and the inside diameter ofsealing contact between the upstream seat ring engaging surface 122 andthe ball portion 40. This is a relatively small area and the seat ringdoes not experience any destructive compressive forces or stresses. Theforegoing dimensional characteristics may be varied as desired toincrease or decrease the annular area involved and thus increase ordecrease the net force of fluid pressure acting on the upstream seatring. In this manner, the amount of seat stress which will beencountered may be tailored to a particular plastic seat material. Inaccordance with the invention, it is desired that the upstream seat ringperform the entire sealing function in the valve closed condition.Therefore, and if there is no fluid leakage at the upstream seat ring,the downstream seat ring could be removed from the valve body with noadverse affects.

As the valve is moved from the closed to the opened position shown inFIGS. 5 and 6, system fluid will enter closure member passage 48 andpass into the valve chamber between valve closure member B and carriersC. O-rings 54 acting against backup rings 56 provide a fluid seal invalve body central passageway between valve body A and closure member B.System fluid will also migrate between both the downstream and upstreamend fittings D and the carriers C on both sides of the associatedO-rings 100. Because of the conformation of the carriers and thepositioning of seat rings 120 relative thereto, fluid pressure forceswill act to urge each of the carriers toward the closure member. Here,however, the area which provides the net force of fluid pressure actingon both the upstream and downstream seats is generally limited to theprojected annular area defined by that portion or band of seat ringengaging surfaces 122 which are in sealing engagement with ball portion40. When the valve is again returned to the closed condition, nomomentary fluid leakage will occur at the upstream seat ring since it isalways maintained in a sealing relationship with ball portion 40.

After some period of valve usage, seat ring engaging surfaces 122 willmore precisely conform to the surface of spherical or ball portion 40 tothereby increase the annular area of sealing contact therebetween. Suchchange will enhance the overall seat ring sealing characteristics andany wear or changes occurring in seat ring engaging surfaces 122 will beautomatically compensated for by the plurality of partially stresseddisc springs 110,112 and 114.

In the event a fluid leak should occur at the upstream seat ring whenthe valve is in the closed condition, downstream seating by thedownstream seat ring will prevent fluid leakage outwardly through thedownstream branch of the valve body. In that case, fluid pressure willurge the downstream carrier C toward closure member B to enhance orincrease the degree of sealing contact between the downstream seat ring120 and ball portion 40. Under this condition, the area which providesthe net force of fluid pressure acting on the downstream seat ringcomprises the annulus defined between the outer diameter of sealingcontact by the downstream seat ring engaging surface with the ballportion and the outer diameter of the associated carrier tail portion62.

Closure member B is, of course, positioned in valve body centralpassageway 20 solely by the action of seat rings 120 being urged againstball portion 40. The O-ring 54 and backup ring 56 disposed in groove 50of each trunnion 42,44 prevent fluid pressure from within the valve bodyinterior, i.e., at the area of the ball portion, to pass outwardlytherefrom between the trunnions and central passageway 20. Because ofthis structural relationship, the closure member is pressure balancedand is not urged by fluid pressure either further into or out of thecentral passageway. This feature is important because it renders thevalve blowout proof in two ways. First, there is no unbalanced pressureforce to urge the closure member out of the bottom of the valve body.Second, should an O-ring leak occur at trunnion 42, and should leak port142 be plugged and not vent this leakage as previously described, theclosure member is still trapped between the opposed seat rings 120. As aresult, while the seat rings may leak because the ball is urged out bypressure, the valve closure member is held by the seat rings and willnot blow out.

FIG. 7 shows a modified valve construction which incorporates theconcept of the subject invention thereinto. For ease of illustration andappreciation of this alternative, like components are identified by likenumerals with a primed (') suffix and new components are identified bynew numerals.

More particularly, FIG. 7 shows a three-way ball valve wherein centralpassageway 20' in valve body A' is threaded as at 170 to define a thirdvalve body branch. This third branch is adapted to have a fluid systemline affixed thereto by a conventional fitting.

Valve closure member B' is also slightly modified in that cylindricalportions or trunnions 42',44' do not include any seal means for sealingagainst the side wall of valve body central passageway 20'. In addition,the fluid passage extending through the closure member is comprised of afirst portion 174 extending axially through the valve closure memberbetween trunnions 42',44' and a second portion 176 extending radially ofball portion 40' in communication with first portion 174. Thisarrangement thus allows a fluid line associated with the valve body atthreaded area 170 to be selectively placed in fluid communication witheach of branches 12',14'. The stop surfaces on handle F also requiremodification to accommodate the necessary rotational capabilities forclosure member B'.

In this particular alternative embodiment, a different stem G isemployed. Specifically, the stem includes a solid cylindrical bodyportion 180 closely rotatably received in smaller diameter portion 26'of the central passageway. A circumferential groove 182 on this bodyportion receives an O-ring seal 184 and a backup ring 186 to effect stemsealing in the central passageway. This sealing is important sincetrunnion 42' does not include any seal means and system fluid wouldotherwise be permitted to escape between the stem and centralpassageway.

A radially outward extending flange 190 having a circular cross-sectionof a diameter slightly less than central passageway 20' is provided atthe stem inner end. A lateral groove 192 is included in the end face offlange 190 to receive tange 52' of the valve closure member in the samemanner previously described to place the stem and closure member incooperative engagement with each other. An annular stem bearing 194 isinterposed between flange 190 and the central passageway shoulder tobetter facilitate ease of stem rotation.

Stem body portion 180 further includes an outer or handle receiving end196 disposed outwardly of the valve body adapted to receive handle F' inthe manner previously described. When the valve is assembled as shown inFIG. 6, the dimensions held on the stem, the closure member, the valvebody and the handle prevent the end face of flange 190 from directlyengaging the upper face of the valve closure member. The connectedrelationship between these two components is effected solely betweentang 52' and receiving groove 192. This relationship prevents anypushing of the stem into the valve from disturbing the sealed contact orrelationship between seat rings 120' and ball portion 40' as couldotherwise occur when flange 190 engaged the upper end of the closuremember.

When the three-way valve of FIG. 7 is installed in a fluid system sothat the branch defined at threaded area 170 comprises the upstream orinlet branch, and with closure member B' rotated to a valve closedposition, system fluid will be prevented from exiting the valve ateither of branches 12', 14'. In this particular installation, the seatrings associated with each of valve body branches 12', 14' function asdownstream seats. System fluid will pass through fluid passage first andsecond portions 174,176 into the valve chamber and will migrate betweencentral passageway 20' and trunnions 42', 44' so as to substantiallyfill the valve chamber radially outward of the outer diameter of sealingcontact between seat ring engaging surfaces 122' and ball portion 40'.At the same time, fluid will migrate around and between seat ringcarriers C' and end fittings D' up to the area of O-rings 100' to urgethe O-rings against backup rings 102'. In the capacity of downstreamseats, fluid pressure will urge both of carriers C' toward closuremember B' to enhance or increase the degree of sealing contact betweenengaging surfaces 122' of seat rings 120' and ball portion 40'. The areawhich provides the net force of fluid pressure acting on the seat ringsis provided by the annular area between the outer diameter of sealingcontact by the seat ring engaging surfaces with the ball portion and theouter diameter of the associated carrier tail portion 62'.

When the valve is opened to the position shown in FIG. 7, system fluidmay pass through the valve and exit from branch 12'. System fluidpressure will still act to urge both seat rings toward engagement withthe ball portion. The area which provides the net force of fluidpressure against the seat ring associated with branch 12' is generallyequal to the projected area of contact between the seat ring engagingsurface and the ball portion. The net force of fluid pressure acting onthe seat ring associated with branch 14' remains substantially the sameas described above for the valve closed condition.

The three-way valve shown in FIG. 7 may also be installed in a fluidsystem so that one of branches 12',14' comprises the upstream or inletbranch with the other of branches 12',14' and branch 170 comprisingdownstream branches. In that case, and with the valve in the closedcondition, the seat ring associated with the inlet branch will functionas an upstream seat in the same manner previously described above withreference to FIGS. 5 and 6. Thus, the upstream seat ring will desirablyperform the entire sealing function and will experience a net fluidpressure force urging it into sealing engagement with ball portion 40'.As before, the area which provides the net force of fluid pressureacting on the upstream seat ring is the annular area defined by thediameter across the associated seal chamber 86' and the inside diameterof sealing contact between the upstream seat ring engaging surface andball portion 40'.

When the valve is moved to the open condition of FIG. 7, and with branch12' comprising the inlet branch, seat ring 120' associated with thisbranch continues to function as an upstream seat. However, due to systemfluid migration inside the valve, the area which provides the net forceof fluid pressure acting against the seat ring in urging it into contactwith the ball portion is generally equal to the projected area of seatring engaging surface contact with the ball portion. Seat ring 120'associated with branch 14' will continue to function as a downstreamseat which experiences a net fluid pressure force urging it into sealingengagement with the ball portion.

While the arrangement shown in FIG. 7 is for a three-way valve, itshould be appreciated that the valve body may be configured to includeadditional branches so that a four or even five-way valve may beadvantageously provided. Such modifications do not, however, in any waydepart from the overall intent or scope of the present invention.

When using the subject new high pressure ball valve concept described indetail hereinabove, substantially higher pressure ratings for a valveemploying plastic seat rings are realized. In that regard, the valve maybe rated and used with pressures of up to 6000 psi without damaging anyof the internal valve components. This rating is substantially higherthan prior known ball valves utilizing plastic seats or seat rings. Inaddition, the subject new valve construction is relatively simple indesign and utilizes a plurality of interchangeable components. Thus, thebasic valve concept is adaptable to use in a wide variety of specificvalving applications in a broad range of environments. Moreover, thesubject new valve construction allows the seat ring stress to betailored or controlled for accommodating particular seat ring materials.These capabilities comprise substantial improvements over many priorvalves having high pressure capabilities.

The invention has been described with particular reference to preferredand alternative embodiments. Obviously, modifications and alterationswill occur to others upon a reading and understanding of thisspecification. It is intended to include all such modifications andalterations insofar as they come within the scope of the appended claimsor the equivalents thereof.

Having thus described the invention, it is now claimed:
 1. A high pressure ball valve comprising:a valve body having a cylindrical first flow passageway and a cylindrical central passageway extending therethrough in a generally normal relative relationship and in communication with each other, the opposite ends of said first passageway defining a pair of valve body branches; a valve closure member received in said central passageway and being selectively rotatable about the central passageway axis, said closure member having a spherical ball portion disposed in said first passageway and a pair of cylindrical trunnions disposed on opposite sides of said ball portion in said central passageway, said ball portion including a fluid passage therethrough and one of said trunnions including means for connecting said closure member to control means; control means in operative communication with said valve closure member connecting means for allowing selective rotation of said closure member to move said fluid passage in said ball portion between valve open and closed conditions; a pair of radially inward extending annular shoulders in said first passageway located generally equal distances from said ball portion, each said shoulder being circumferentially continuous and having a surface normal to the axis of said first passageway facing said ball portion; a pair of seat ring carriers disposed in said first passageway with one of said carriers positioned at each area of communication of said first passageway with said central passageway, each carrier including an axial fluid flow opening therethrough and a radially outward extending annular face compatible with and facing the said surface of an associated one of said shoulders, said carriers each further including an annular seat ring receiving groove facing said ball portion and a cylindrical tail portion extending axially of said first passageway away from said ball portion in a radially inwardly spaced relation to said first flow passageway to form a cylindrical seal chamber; a plurality of partially stressed disc springs interposed between each shoulder surface and the annular face of the associated carrier for urging said carriers axially of said first passageway toward said ball portion, each disc spring having a central opening and in its unstressed condition having a truncated conical shape, said disc springs being positioned so that the smaller diameter ends of alternating ones thereof face in opposite directions; a deformable annular seat ring closely received in the seat ring receiving groove of each carrier with said seat rings each including a continuous engaging surface facing said ball portion and wherein said engaging surface has a spherical conformation in its unstressed condition of a radius less than the radius of said ball portion, said seat ring engaging surfaces being urged into sealing contact so that said surfaces first contact with said ball portion at about the outer diameter of said surfaces during assembly and such contact widening from the outer diameter radially inwardly toward the inner diameter of said surfaces under the influence of said disc springs and fluid pressure loads, said sealing contact occurring at least at a diameter across the engaging surface of each seat ring which is smaller than the diameter across the associated seal chamber, said seat rings locating said closure member ball portion in said first passageway and retaining said closure member in said central passageway; seal means interposed between each carrier tail portion and the valve body, in the associated seal chamber, and said seal means each including at least one annular seal ring adapted to be axially shifted between defined limits in response to fluid pressure exerted thereagainst; and, means providing upstream fluid pressure to the upstream one of said seal chambers upstream of its seal means when said closure member is in its closed condition to further urge the associated seat ring toward engagement with said ball portion with a net fluid force, the area which provides the net force of fluid pressure for such further urging being limited to a predetermined annular area which will prevent the application of destructive compressive loads to the seat ring, and said predetermined annular area for said upstream seat ring in said valve closed position being defined between the diameter across the associated seal chamber and the inside diameter of the upstream seat ring engaging surface.
 2. The ball valve as defined in claim 1 wherein each seat ring engaging surface contacts said ball portion by an annular engaging band, said band having an outer diameter greater than the outside diameter of the associated carrier tail portion.
 3. The ball valve as defined in claim 2 wherein one of said seat rings comprises an upstream seat ring and the other seat ring comprises a downstream seat ring with said upstream seat ring adapted to perform substantially the entire valve sealing function in the valve closed condition.
 4. The ball valve as defined in claim 3 wherein in said valve open condition with said pair of valve body branches in communication with each other, said predetermined annular area for said upstream and downstream seat rings generally comprises the projected area of said annular engaging bands.
 5. The ball valve as defined in claim 3 wherein said predetermined annular area for said downstream seat ring is defined between the outside diameter of the downstream seat ring engaging band and the outside diameter of the associated carrier tail portion.
 6. The ball valve as defined in claim 5 wherein that portion of said central passageway receiving the other of said trunnions defines a downstream third valve body branch, further wherein in said valve open condition with the branch associated with said upstream seat ring communicating with said third valve body branch, said predetermined area for said upstream seat ring comprises the projected area of said upstream seat ring annular engaging band.
 7. The ball valve as defined in claim 2 wherein that portion of said central passageway receiving the other of said trunnions defines a third valve body branch, said third valve body branch comprising an upstream branch with said pair of seat rings comprising downstream seat rings, said predetermined annular area in said valve closed condition for said seat rings being defined between the outside diameter of the engaging band on each seat ring and the outside diameter of the associated carrier tail portion.
 8. The ball valve as defined in claim 7 wherein in said valve open condition with said third valve body branch in communication with one of said pair of branches, said predetermined annular area for the seat ring associated with said one branch comprises the projected area of said one branch associated seat ring annular engaging band.
 9. The ball valve as defined in claim 1 wherein the ones of said disc springs cooperating directly with said shoulder surfaces have the smaller diameter ends facing said ball portion.
 10. The ball valve as defined in claim 1 wherein said shoulders and seal chambers are defined by removable end fittings received in said first passageway.
 11. The ball valve as defined in claim 10 further including an annular carrier gland interposed between each carrier tail portion and the side wall of the associated seal chamber, each gland accommodating slight transverse shifting of the associated carrier to facilitate a locating action by said seat rings against said ball portion.
 12. The ball valve as defined in claim 11 wherein each seal means further includes a pair of annular backup rings having said seal ring interposed therebetween, said backup rings having an axially spaced relationship to each other greater than the transverse cross-section of said seal ring and establishing said defined limits.
 13. The ball valve as defined in claim 1 wherein said closure member trunnions each include a circumferential groove having sealing means disposed therein in sealing cooperation with the side wall of said central passageway.
 14. The ball valve as defined in claim 13 further including a backup ring received in each trunnion groove on the side of said seal means remote from said ball portion.
 15. The ball valve as defined in claim 14 wherein said closure member is pressure balanced in said central passageway by system fluid passing through said valve, whereby there are no pressure forces tending to urge the closure member outwardly from the valve body central passageway.
 16. The ball valve as defined in claim 1 wherein said control means comprises an operating stem rotatably received in said central passageway and having an outer end disposed outwardly of said body, said operating stem including a radially outward extending circumferential flange adjacent the stem inner end cooperable with a radially inward extending flange in said central passageway for preventing withdrawal of said stem from said central passageway in the direction of said stem outer end.
 17. The ball valve as defined in claim 16 further including stem bearing interposed between said stem flange and central passageway shoulder.
 18. The ball valve as defined in claim 16 further including a stem seal sealingly interposed between said stem and said central passageway.
 19. The ball valve as defined in claim 16 further including a journal bearing interposed between said stem and central passageway for inhibiting metal to metal sliding contact between said stem and the side wall of said central passageway when said stem is rotated for moving said closure member between said valve open and closed conditions.
 20. The ball valve as defined in claim 16 wherein said stem further includes a vent opening extending axially thereof from the end face of said flange toward said stem outer end and communicating with at least one radial cross hole in said stem disposed externally of said valve body, said vent opening allowing system fluid bypassing said one trunnion to vent to atmosphere and prevent the exertion of unbalanced pressure forces against said closure member in said central passageway.
 21. The ball valve as defined in claim 16 wherein a control handle is secured to said stem outer end with said handle including arcuately spaced apart stop surfaces, said valve body including at least one handle stop engagable by said stop surfaces when said handle is moved between preselected rotated positions defining said valve open and closed conditions.
 22. The ball valve as defined in claim 16 wherein one of said valve stem inner end and said valve closure member one trunnion includes an axial tang and the other of said stem inner end and one trunnion includes a tang receiving slot, said tang being received in said slot for interconnecting said stem with said valve closure member and comprising the only contact between said stem and closure member, whereby the located relationship of said closure member ball portion by said seat rings will not be disturbed by limited axial movement of said stem.
 23. The ball valve as defined in claim 1 wherein said valve closure member fluid passage includes a first portion extending therethrough between said closure member trunnions and a second portion in said ball portion extending radially outward from said passage first portion, that portion of said central passageway receiving the other of said trunnions defining a third valve body branch and including means adapted to connect a fluid fitting thereto, whereby said valve may accommodate fluid flow between at least three fluid lines. 